1. Field of the Invention
The present invention relates to surgical stapling and cutting instruments adapted for use in the diagnosis and therapy of pathologies treated by stapled resection. More particularly, the invention relates to a lockout mechanism for utilization in conjunction with surgical stapling and cutting instruments.
2. Description of the Prior Art
Surgical stapling and cutting instruments are commonly utilized in the diagnosis and treatment of pathologies treated by stapled resection. Surgical stapling and cutting instruments provide a mechanism to extend the transluminal exploitation of mechanical suturing devices introduced via the anal canal, mouth, stomach and service accesses. Although surgical stapling and cutting instruments are most commonly utilized with rectal pathologies, surgical stapling and cutting instruments may be used in a variety of environments.
Over time, surgical stapling and cutting instruments have been developed. These instruments generally include a support frame, an anvil attached to the support frame and a cartridge housing carrying a plurality of staples. The instruments also include a driver within the cartridge housing which pushes all of the staples out simultaneously into the anvil to form the staples into a generally B-shape, suturing tissue together. In addition, these instruments include approximation mechanisms that allow for the cartridge housing and anvil to move relative to each other to accept tissue therebetween. Finally, the instruments include a firing mechanism for moving the driver forward to form the staples against the anvil.
In addition to the basic components of the stapling and cutting instruments, these products need a lockout mechanism permitting activation and/or deactivation of the approximation means such that the cartridge module may be utilized as a clamp when needed during an emergency. However, the lockout mechanism is designed such that the firing mechanism only works for a cartridge module that has not been previously used.
Current surgical stapling instruments include a firing bar lockout that is activated by the driver. When a new cartridge module is loaded into the instrument, the location of the driver, as it relates to the cartridge module in the instrument, interferes with the lockout arm in a way so as to let the instrument fire staples. After the instrument fires staples, the location of the driver moves distally in a way that it no longer interferes with the lockout arm. The lockout arm moves to a position that now interferes with the firing bar, but prevents the firing bar from moving distally. However, prior art lockout mechanisms do not provide a clear indication that the instrument has been previously fired. As such, prior lockout mechanisms may be simply confused with an instrument that has been jammed.
In addition, prior lockout systems require the device to survive high stress if the user should try to defeat the lockout mechanism. As will be discussed below in greater detail, the present lockout mechanism disengages the firing mechanism altogether removing any force transmission that would require the device to survive high loads.
As such, a need exists for an improved lockout mechanism that provides a clear indication that the lockout mechanism has been activated and overcomes the other shortcomings of prior art lockout mechanisms. The present invention provides such a lockout mechanism.